Pectoralis minor muscle

From Wikipedia, the free encyclopedia

Pectoralis minor
Latin	musculus pectoralis minor
Gray's	subject #122 438
Origin	3rd to 5th ribs, near their costal cartilages
Insertion	medial border and superior surface of the coracoid process of the scapula
Artery	Pectoral branch of the thoracoacromial trunk
Nerve	Medial pectoral nerve (C8, T1)
Actions	It stabilizes the scapula by drawing it inferiorly and anteriorly against the thoracic wall.

The Pectoralis minor is a thin, triangular muscle, situated at the upper part of the chest, beneath the Pectoralis major.

Contents 1 Origin and insertion 2 Relations 3 Actions 4 Variations 5 Additional images 6 External links

[edit] Origin and insertion

It arises from the upper margins and outer surfaces of the third, fourth, and fifth ribs, near their cartilages and from the aponeuroses covering the Intercostalis.

The fibers pass upward and lateralward and converge to form a flat tendon, which is inserted into the medial border and upper surface of the coracoid process of the scapula.

[edit] Relations

The pectoralis minor muscle is covered anteriorly (superficially) by the clavipectoral fascia. The medial pectoral nerve pierces the pectoralis minor and the clavipectoral fascia.

[edit] Actions

The Pectoralis minor depresses the point of the shoulder, drawing the scapula downward and medialward toward the thorax, and throwing the inferior angle backward.

[edit] Variations

Origin from second, third and fourth or fifth ribs. The tendon of insertion may extend over the coracoid process to the greater tubercle. May be split into several parts. Absence rare.

[edit] Additional images

Anterior surface of sternum and costal cartilages.	Left scapula. Costal surface.	Deep muscles of the chest and front of the arm, with the boundaries of the axilla.	The axillary artery and its branches.
The veins of the right axilla, viewed from in front.	The right brachial plexus with its short branches, viewed from in front.	Nerves of the left upper extremity.

[edit] External links

• LUC pcmn
• UWASH pectoralisminor
• 13631566 at GPnotebook
• SUNY Figs 04:04-05
• SUNY Figs 05:02-08
• SUNY Labs 05:ov-0200
• SUNY Labs 05:01-0102
• Slide
• Muscles/PectoralisMinor at exrx.net

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated.

v • d • e List of muscles of upper limbs Vertebral column trapezius · latissimus dorsi · rhomboid (major, minor) · levator scapulae Thoracic cavity pectoralis major · pectoralis minor · subclavius · serratus anterior Shoulder deltoid · rotator cuff (supraspinatus, infraspinatus, teres minor, subscapularis) · teres major Arm Anterior coracobrachialis · biceps brachii · brachialis Posterior triceps brachii · anconeus Forearm Anterior superficial: pronator teres · palmaris longus · flexor carpi radialis · flexor carpi ulnaris · flexor digitorum superficialis deep: pronator quadratus · flexor digitorum profundus · flexor pollicis longus Posterior superficial: mobile wad (brachioradialis, extensor carpi radialis longus and brevis) · extensor digitorum · extensor digiti minimi · extensor carpi ulnaris deep: supinator · anatomical snuff box (abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus) · extensor indicis Hand Lateral volar thenar (opponens pollicis, flexor pollicis brevis, abductor pollicis brevis) · adductor pollicis Medial volar hypothenar (opponens digiti minimi, flexor digiti minimi brevis, abductor minimi digiti) · palmaris brevis Intermediate lumbrical · interossei (dorsal, palmar)