Elbow Anatomy
ELBOW JOINT
Definition
· Complex hinge joint
· Connects upper arm to the forearm
· Joint is surrounded by a joint capsule
· Hinge joint consists of 3 individual joints that go together to make the elbow
1. Humeroulnar joint – between the humerus and ulna
2. Humeroradial joint – between the humerus and radius
3. Proximal radioulnar joint – between the proximal radius and
the ulna
Movement
· Flexion
· Extension
· Pronation of the hand
· Supination of the hand
Articulations
· Humerus articulates with the ulna (forms the humeroulnar joint)
· Humerus articulates with the radius (humeroradial joint)
· Proximal radius articulates with the ulna (Proximal radioulnar joint)
Function
· Allow for bending, extending, and rotating the arm 1
Definition
· Complex hinge joint
· Connects upper arm to the forearm
· Joint is surrounded by a joint capsule
· Hinge joint consists of 3 individual joints that go together to make the elbow
1. Humeroulnar joint – between the humerus and ulna
2. Humeroradial joint – between the humerus and radius
3. Proximal radioulnar joint – between the proximal radius and
the ulna
Movement
· Flexion
· Extension
· Pronation of the hand
· Supination of the hand
Articulations
· Humerus articulates with the ulna (forms the humeroulnar joint)
· Humerus articulates with the radius (humeroradial joint)
· Proximal radius articulates with the ulna (Proximal radioulnar joint)
Function
· Allow for bending, extending, and rotating the arm 1
RADIAL HEAD
Definition
· Located at the proximal end of the radius
· Concave in shape
· Lateral surface of the head is a smooth cylinder
Movement
· Lateral surface of the head rotates against the radial notch of the ulna
Articulations
· Articulates with the capitulum of the humerus
· Articulates with the radial notch of the ulna
Function
· Allows for rotation of the radius against the ulna proximally to allow for supination
and pronation 1
Definition
· Located at the proximal end of the radius
· Concave in shape
· Lateral surface of the head is a smooth cylinder
Movement
· Lateral surface of the head rotates against the radial notch of the ulna
Articulations
· Articulates with the capitulum of the humerus
· Articulates with the radial notch of the ulna
Function
· Allows for rotation of the radius against the ulna proximally to allow for supination
and pronation 1
RADIAL NECK & TUBEROSITY
Definition
· The radial neck is located at the proximal end of the radius
· Radial neck is the skinnier portion of the radius immediately distal to the radial head
· The radial tuberosity is located at the proximal end of the radius, on the medial side
· Radial tuberosity is a rough surface projection off the side of the radius
Articulations
· Articulates with the biceps brachii tendon
Function
· Attachment site for the biceps brachii tendon 1
*See above image captioned Proximal end of radius & ulna for an image of the radial neck and tuberosity
Definition
· The radial neck is located at the proximal end of the radius
· Radial neck is the skinnier portion of the radius immediately distal to the radial head
· The radial tuberosity is located at the proximal end of the radius, on the medial side
· Radial tuberosity is a rough surface projection off the side of the radius
Articulations
· Articulates with the biceps brachii tendon
Function
· Attachment site for the biceps brachii tendon 1
*See above image captioned Proximal end of radius & ulna for an image of the radial neck and tuberosity
STYLOID PROCESS OF THE RADIUS & ULNA
Definition
· Ulnar styloid process is located on the posteriomedial side of the ulnar head
· Radius styloid process is located at the distal end of the radius
· Small process that is shaped like a writing instrument
· Ligaments of the wrist attach here
Articulations
· Radius styloid process articulates with the ulna and the carpal bones
Function
· Attachment point for ligaments of the wrist. 1
Definition
· Ulnar styloid process is located on the posteriomedial side of the ulnar head
· Radius styloid process is located at the distal end of the radius
· Small process that is shaped like a writing instrument
· Ligaments of the wrist attach here
Articulations
· Radius styloid process articulates with the ulna and the carpal bones
Function
· Attachment point for ligaments of the wrist. 1
ULNAR HEAD
Definition
· An oval articular surface on the distal end of the ulna
· Located on the posterior, medial side of the distal forearm
Articulations
· Articulates with the radius and the wrist bones
Function
· Posteriomedial side of the ulnar head has a styloid process where wrist ligaments attach to
· Articulation surface 1
*See above image captioned Radius and Ulna.
ULNAR TUBEROSITY
Definition
· Prominence at the lower boarder of the anterior surface of the coronoid process of the ulna
Articulations
· Articulates with the brachialis muscle tendon
Function
· Insertion point for the brachialis muscle 2
Definition
· Prominence at the lower boarder of the anterior surface of the coronoid process of the ulna
Articulations
· Articulates with the brachialis muscle tendon
Function
· Insertion point for the brachialis muscle 2
LATERAL ULNAR COLLATERAL LIGAMENT (LUCL)
Definition
· Works with the radial collateral ligament, annular ligament, and the accessory lateral ligament as a primary stabilizer of the elbow for external rotation forces
Origin
· Lateral epicondyle
Insertion
· Tubercle of the supinator crest of the ulna
Function
· Stabilizes the elbow against posterolateral rotational instability 3
Definition
· Works with the radial collateral ligament, annular ligament, and the accessory lateral ligament as a primary stabilizer of the elbow for external rotation forces
Origin
· Lateral epicondyle
Insertion
· Tubercle of the supinator crest of the ulna
Function
· Stabilizes the elbow against posterolateral rotational instability 3
RADIAL COLLATERAL LIGAMENT
Definition
· Ligament of the elbow
· Made of a fibrous band extending from the lateral epicondyle to the annunal ligament
Origin
· Lateral epidcondyle of the humerus
Insertion
· Annual ligament of the radius
Function
· Strengthens the side of the wall of the elbow joint capsule
· Stabilizes the lateral side of the elbow joint
· Prevents medial flexion and lateral translation of the elbow joint
· Stabilizes the elbow during flexion 4
See image under "Lateral Ulnar Collateral Ligament"
Definition
· Ligament of the elbow
· Made of a fibrous band extending from the lateral epicondyle to the annunal ligament
Origin
· Lateral epidcondyle of the humerus
Insertion
· Annual ligament of the radius
Function
· Strengthens the side of the wall of the elbow joint capsule
· Stabilizes the lateral side of the elbow joint
· Prevents medial flexion and lateral translation of the elbow joint
· Stabilizes the elbow during flexion 4
See image under "Lateral Ulnar Collateral Ligament"
ANNULAR LIGAMENT
Definition
· Thick band that encircles the head of the radius and anchors it to the radial notch of the ulna
Origin
· Attached to the anterior margin of the radial notch of the ulna
Insertion
· Posterior margin of the trochlear notch of the ulna
Function
· Encircles the head of the radius
· Keeps the head in contact with the radial notch of the ulna
· Anchors and stabilizes the proximal radiounlar joint 5
See image under "Lateral Ulnar Collateral Ligament"
Definition
· Thick band that encircles the head of the radius and anchors it to the radial notch of the ulna
Origin
· Attached to the anterior margin of the radial notch of the ulna
Insertion
· Posterior margin of the trochlear notch of the ulna
Function
· Encircles the head of the radius
· Keeps the head in contact with the radial notch of the ulna
· Anchors and stabilizes the proximal radiounlar joint 5
See image under "Lateral Ulnar Collateral Ligament"
BICEPS BRACHII TENDON
Definition
· Two headed tendon that runs the length of the upper arm, from the radius to the scapula
Origin
· Short head = tip of the coracoid process of the scapula
· Long head = from supraglenoid tuberosity of the scapula
Insertion
· Radial tuberosity of the proximal radius
Movement
· When it contracts the moveable end is pulled towards the origin
· Contraction causes the arm to bend at the elbow
Function
· Flexes the elbow
· Supinates the forearm
· Flexes the shoulder
· Works with other muscles of the arm and shoulder to preform these functions 6
Definition
· Two headed tendon that runs the length of the upper arm, from the radius to the scapula
Origin
· Short head = tip of the coracoid process of the scapula
· Long head = from supraglenoid tuberosity of the scapula
Insertion
· Radial tuberosity of the proximal radius
Movement
· When it contracts the moveable end is pulled towards the origin
· Contraction causes the arm to bend at the elbow
Function
· Flexes the elbow
· Supinates the forearm
· Flexes the shoulder
· Works with other muscles of the arm and shoulder to preform these functions 6
CORONOID PROCESS
Definition
· Smaller process that is anterior to the olecranon process
· Triangular eminence that projects from the superior and anterior part of the ulna
Insertions
· Three soft tissue insertions occur at the coronoid process:
o Anterior joint capsule
o Brachialis muscle
o Medial ulnar collateral ligament
Movement
· Extension of the elbow
Function
· Stabilizes the elbow during extension 7
Definition
· Smaller process that is anterior to the olecranon process
· Triangular eminence that projects from the superior and anterior part of the ulna
Insertions
· Three soft tissue insertions occur at the coronoid process:
o Anterior joint capsule
o Brachialis muscle
o Medial ulnar collateral ligament
Movement
· Extension of the elbow
Function
· Stabilizes the elbow during extension 7
CORONOID FOSSA
Definition
· Depression in the surface of the inferior anterior surface of the humerus
· Situated on the front of the bone where the ulna and radius bones of the forearm meet the humerus
Articulations
· Coronoid process during contraction of the biceps/flexion of the forearm
Function
· Function is to receive the coronoid process during extreme flexion of the forearm 8
Definition
· Depression in the surface of the inferior anterior surface of the humerus
· Situated on the front of the bone where the ulna and radius bones of the forearm meet the humerus
Articulations
· Coronoid process during contraction of the biceps/flexion of the forearm
Function
· Function is to receive the coronoid process during extreme flexion of the forearm 8
OLECRANON
Definition
· The “bony” part of the elbow
· Hook like in shape
· It curves around the distal part of the humerus and encapsulates the elbow joint
· Is also a site of muscle attachments
Articulations
· Distal end of the humerus
Movement
· Olecranon cups the distal end of the humerus and rotates around the end like a hinge
Function
· Site of muscle attachments
· Curves around the distal portion of the humerus and encapsulates the elbow joint 9
Definition
· The “bony” part of the elbow
· Hook like in shape
· It curves around the distal part of the humerus and encapsulates the elbow joint
· Is also a site of muscle attachments
Articulations
· Distal end of the humerus
Movement
· Olecranon cups the distal end of the humerus and rotates around the end like a hinge
Function
· Site of muscle attachments
· Curves around the distal portion of the humerus and encapsulates the elbow joint 9
OLECRANON FOSSA
Definition
· Depression in the humerus where the olecranon curves into
Articulations
· Olecranon process of the ulna
Movement
· Receives the olecranon process during extension or straightening of the elbow
Function
· Articulates with the olecranon process to allow for extension and flexion of the forearm
· Ensures that the humeroulnar (the hinge joint at the elbow) does not get crushed when the arm is bent
and flexed 9
Definition
· Depression in the humerus where the olecranon curves into
Articulations
· Olecranon process of the ulna
Movement
· Receives the olecranon process during extension or straightening of the elbow
Function
· Articulates with the olecranon process to allow for extension and flexion of the forearm
· Ensures that the humeroulnar (the hinge joint at the elbow) does not get crushed when the arm is bent
and flexed 9
SYNOVIAL MEMBRANE
Definition
· A thin membrane in freely moving joints that lines the joint capsule and secretes fluid
· Extends from the margin of the articular surface of the humerus
· Lines the coronoid, radial, an olecranon fossae
· Layer of connective tissue that lines the cavities of joints, tendon sheaths, and bursae
· Makes synovial fluid
Articulations
· Lines the ligamentous surfaces of the joint capsule
Movement
· Helps lubricate movement of the joint
Function
· Lubricates joint movement
· Lines the joint capsule 10
Definition
· A thin membrane in freely moving joints that lines the joint capsule and secretes fluid
· Extends from the margin of the articular surface of the humerus
· Lines the coronoid, radial, an olecranon fossae
· Layer of connective tissue that lines the cavities of joints, tendon sheaths, and bursae
· Makes synovial fluid
Articulations
· Lines the ligamentous surfaces of the joint capsule
Movement
· Helps lubricate movement of the joint
Function
· Lubricates joint movement
· Lines the joint capsule 10
HUMERUS TROCHLEA
Definition
· Distal end of the humerus that articulates with the ulna
· Structure resembles a pulley
Articulations
· With the proximal end of the ulna (called the trochlear notch)
Movement
· Flexion and extension of the elbow
Function
· Forms the hinge joint of the elbow with the distal end of the ulna
· Allows for flexion and extension of elbow 11
Definition
· Distal end of the humerus that articulates with the ulna
· Structure resembles a pulley
Articulations
· With the proximal end of the ulna (called the trochlear notch)
Movement
· Flexion and extension of the elbow
Function
· Forms the hinge joint of the elbow with the distal end of the ulna
· Allows for flexion and extension of elbow 11
CAPITULUM
Definition
· Located at the distal end of the humerus
· Small dome-like articular surface 13
Articulations
· Articulates with the head of the radius (called the humeroradial articulation)
Movement
· Flexion and extension
Function
· A groove for articulation with the head of the radius to allow for flexion and extension of the forearm 12
Definition
· Located at the distal end of the humerus
· Small dome-like articular surface 13
Articulations
· Articulates with the head of the radius (called the humeroradial articulation)
Movement
· Flexion and extension
Function
· A groove for articulation with the head of the radius to allow for flexion and extension of the forearm 12
MEDIAL AND LATERAL EPICONDYLE
Definition
· Medial epicondyle:
o Projection on the medial (inner) side of the distal end of the humerus
o A.k.a. “funny bone” 14
· Lateral epicondyle:
o Projection on the lateral (outer) side of the distal end of the humerus 15
Function
· Medial Epicondyle:
o Forms a posterior groove for the ulnar nerve
o Superficial flexor muscles of the anterior antebrachium attach anteriorly 14
· Lateral Epicondyle:
o Anterior attachment site for the tendon of the posterior antebrachial muscles 15
Definition
· Medial epicondyle:
o Projection on the medial (inner) side of the distal end of the humerus
o A.k.a. “funny bone” 14
· Lateral epicondyle:
o Projection on the lateral (outer) side of the distal end of the humerus 15
Function
· Medial Epicondyle:
o Forms a posterior groove for the ulnar nerve
o Superficial flexor muscles of the anterior antebrachium attach anteriorly 14
· Lateral Epicondyle:
o Anterior attachment site for the tendon of the posterior antebrachial muscles 15
MEDIAL AND LATERAL SUPRACONDYLAR RIDGE
Definition
· Medial:
o Medial ridge extending from the shaft of the humerus to the medial
epicondyle 15
· Lateral
o Lateral ridge extending for the shaft of the humerus towards the lateral
epicondyle 16
Function
· Medial
o Attachment site for pronator teres muscle 15
· Lateral
o Attachment site for brachioradialis and extensor carpi radialis longus muscle 16
Definition
· Medial:
o Medial ridge extending from the shaft of the humerus to the medial
epicondyle 15
· Lateral
o Lateral ridge extending for the shaft of the humerus towards the lateral
epicondyle 16
Function
· Medial
o Attachment site for pronator teres muscle 15
· Lateral
o Attachment site for brachioradialis and extensor carpi radialis longus muscle 16
RADIAL FOSSA
Definition
· Small shallow fossa positioned medial and superior to the capitulum
Articulations
· Articulates with the head of the radius (at the radial notch)
Movements
· Radial fossa articulation with the radial notch allows for supination and pronation of forearm
Function
· Margin of the head of the radius rests here when the elbow is flexed 17
Definition
· Small shallow fossa positioned medial and superior to the capitulum
Articulations
· Articulates with the head of the radius (at the radial notch)
Movements
· Radial fossa articulation with the radial notch allows for supination and pronation of forearm
Function
· Margin of the head of the radius rests here when the elbow is flexed 17
BRACHIALIS
Definition
· Muscle of the upper arm
Origin
· Anterior, distal half of the humerus
Insertion
· Coronoid process and tuberosity of the ulna
Movement
· Flexes the forearm at the elbow
Function
· Flexion of the forearm 18
Definition
· Muscle of the upper arm
Origin
· Anterior, distal half of the humerus
Insertion
· Coronoid process and tuberosity of the ulna
Movement
· Flexes the forearm at the elbow
Function
· Flexion of the forearm 18
OLECRANON BURSA
Definition
· Bursa is a fluid filled sac that cushions and lubricates areas of the body
where friction is likely to occur
· Located on the posterior surface of the olecranon
· Found between the point of the elbow (the olecranon) and the skin
Function
· Cushions and lubricates the area between the skin and the olecranon to
reduce friction 19
Definition
· Bursa is a fluid filled sac that cushions and lubricates areas of the body
where friction is likely to occur
· Located on the posterior surface of the olecranon
· Found between the point of the elbow (the olecranon) and the skin
Function
· Cushions and lubricates the area between the skin and the olecranon to
reduce friction 19
COMMON EXTENSOR LATERAL
Definition
· Tendon of the elbow
· Tendon involved in lateral epicondylitis (tennis elbow)
Origin
· Lateral epicondyle
Function
· Attachment site for extensor tendons 20
Definition
· Tendon of the elbow
· Tendon involved in lateral epicondylitis (tennis elbow)
Origin
· Lateral epicondyle
Function
· Attachment site for extensor tendons 20
COMMON FLEXOR LATERAL
Definition
· Tendon in the forearm
Origin
· Medial epicondyle of humerus
Movement
· Flexion
Function
· Attachment site for tendons of the forearm
· Flexion of:
o Phalanges
o Metacarpal phalangeal hinge joints
o Wrist joint 20
Definition
· Tendon in the forearm
Origin
· Medial epicondyle of humerus
Movement
· Flexion
Function
· Attachment site for tendons of the forearm
· Flexion of:
o Phalanges
o Metacarpal phalangeal hinge joints
o Wrist joint 20
Elbow Nerves:
ULNAR NERVE
Definition
· Nerve of the arm that is responsible for innervation of the forearm, wrist, and hand
· Is a continuation of the medial cord
· Descends down the medial side of the arm
· Passes posterior to the medial epicondyle
· Passes down the forearm alongside the ulna
· At the wrist it travels superficially to the flexor retinaculum
Movement
· Gives rise to branches that flex the hand at the wrist and the fingers
· Innervates most of the muscles that control intricate hand movements
Function
· Innervates muscles of the forearm, wrist, and hand 21
Definition
· Nerve of the arm that is responsible for innervation of the forearm, wrist, and hand
· Is a continuation of the medial cord
· Descends down the medial side of the arm
· Passes posterior to the medial epicondyle
· Passes down the forearm alongside the ulna
· At the wrist it travels superficially to the flexor retinaculum
Movement
· Gives rise to branches that flex the hand at the wrist and the fingers
· Innervates most of the muscles that control intricate hand movements
Function
· Innervates muscles of the forearm, wrist, and hand 21
MEDIAN NERVE
Definition
· One of the three major nerve of the forearm and hand
· Runs from the axilla to the hand
· Compression of this nerve causes carpal tunnel syndrome
Origin
· Brachial plexus in axilla
Insertion
· Phalanges
Movement
· Movement of hand and forearm muscles
Function
· Innervates the intrinsic muscles of the hand 22
Definition
· One of the three major nerve of the forearm and hand
· Runs from the axilla to the hand
· Compression of this nerve causes carpal tunnel syndrome
Origin
· Brachial plexus in axilla
Insertion
· Phalanges
Movement
· Movement of hand and forearm muscles
Function
· Innervates the intrinsic muscles of the hand 22
ANTERIOR AND POSTERIOR INTEROSSEUOUS NERVE
Definition
· Anterior Interosseous Nerve:
o Branch of the median nerve
· Posterior Interosseous Nerve:
o Branch of the radial nerve
o Supplies extrinsic wrist extensors
Origin
· Anterior:
o Arises from the medial nerve distal to the antecubital fossa
· Posterior:
o Arises from radial nerve at the lateral epicondyle
Definition
· Anterior Interosseous Nerve:
o Branch of the median nerve
· Posterior Interosseous Nerve:
o Branch of the radial nerve
o Supplies extrinsic wrist extensors
Origin
· Anterior:
o Arises from the medial nerve distal to the antecubital fossa
· Posterior:
o Arises from radial nerve at the lateral epicondyle
Insertion
· Anterior
o Terminates in the pronator quadratus muscle at the wrist
Movement
· Anterior
o Innvervates the flexor pollicis longus, flexor digitorum profundus, pronator quadratus
· Posterior
o Innvervates the wrist extensors
Function
· Motor nerves 23
· Anterior
o Terminates in the pronator quadratus muscle at the wrist
Movement
· Anterior
o Innvervates the flexor pollicis longus, flexor digitorum profundus, pronator quadratus
· Posterior
o Innvervates the wrist extensors
Function
· Motor nerves 23
Elbow Joint Anatomy Tutorial
References
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