Arm

IMAGING ANATOMY

Overview

• Muscles of upper arm are divided into anterior and posterior compartments

Anatomy Relationships

• Anterior compartment of arm

Coracobrachialis muscle

– Origin: Coracoid process tip, in common with and medial to short head biceps tendon

– Insertion: Medial surface of humeral midshaft, between brachialis and triceps muscle origins

– Nerve supply: Musculocutaneous nerve, perforates muscle

– Blood supply: Brachial artery, muscular branches

– Action: Flexes and adducts shoulder, supports humeral head in glenoid

Biceps muscle, short head

– Origin: Coracoid process tip, in common with and lateral to coracobrachialis tendon

– Insertion: Radial tuberosity after joining long head

– Nerve supply: Musculocutaneous nerve

– Blood supply: Brachial artery, muscular branches

– Action: Flexes elbow and shoulder, supinates forearm

Biceps muscle, long head

– Origin: Predominantly supraglenoid tubercle, also superior glenoid labrum and coracoid base

– Insertion: Radial tuberosity after joining with short head

– Tendon runs along bicipital groove, which is covered by transverse ligament

– Transverse ligament spans proximal end of bicipital groove and comprises deeper layer formed from subscapularis tendon fibers and superficial fibrous layer in continuity with supraspinatus tendon and coracohumeral ligament

– Nerve supply: Musculocutaneous nerve

– Blood supply: Brachial artery, muscular branches

– Action: Flexes elbow, supinates forearm

– Variants, biceps muscle: 3rd head in 10% arising at upper medial aspect of brachialis muscle; 4th head can arise from lateral humerus, bicipital groove, or greater tuberosity

Brachialis muscle

– Origin: Distal 1/2 of anterior humeral shaft and 2 intermuscular septa

– Insertion: Tuberosity of ulna and anterior surface of coronoid process

– Nerve supply: Musculocutaneous nerve plus branch of radial nerve

– Blood supply: Brachial artery, muscular branches, and recurrent radial artery

– Action: Flexes forearm

– Covers anterior aspect of elbow joint
• Posterior compartment of arm

Triceps muscle, long head

– Origin: Infraglenoid tubercle of scapula

– Insertion: Proximal olecranon and deep fascia of arm after joining with lateral and medial heads

– Nerve supply: Radial nerve

– Blood supply: Deep brachial artery branches

– Action: Elbow extension, adducts humerus when arm is extended

Triceps muscle, lateral head

– Origin: Posterior and lateral humeral shaft, lateral intermuscular septum

– Insertion: Proximal olecranon and deep fascia of arm after joining with long and medial heads

– Nerve supply: Radial nerve

– Blood supply: Deep brachial artery branches

– Action: Elbow extension

Triceps muscle, medial head

– Origin: Posterior humeral shaft from teres major insertion to near trochlea, medial intermuscular septum

– Insertion: Proximal olecranon and deep fascia of arm after joining with lateral and long heads

– Nerve supply: Radial and branches of ulnar nerve

– Blood supply: Deep brachial artery branches

– Action: Elbow extension

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Apr 9, 2020 | Posted by admin in MUSCULOSKELETAL IMAGING | Comments Off

IMAGING ANATOMY

Overview

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Arm

Arm

Anatomy Relationships

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Radiology Key

Fastest Radiology Insight Engine

Arm

Arm

IMAGING ANATOMY

Overview

Anatomy Relationships

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