Posterior compartment of the arm

Posterior compartment of the arm
Cross-section through the middle of upper arm.
Latin	compartimentum brachii posterius
Artery	profunda brachii
Nerve	muscular branches of the radial nerve

The posterior compartment of the arm is an anatomic compartment which contains muscles which are all supplied by the radial nerve. This compartment is also known as the "extensor compartment", extension being its main action.

Contents

The muscles of this compartment are the triceps brachii and anconeus muscle.

• The triceps brachii is a large muscle containing three heads (lateral, medial, and middle).

• The anconeus is a small muscle that stabilizes the elbow joint during movement. Some embryologists consider it as the fourth head of the triceps brachii. As the upper and lower limbs have similar embryological origins and the lower limb contains the quadriceps femoris muscle (the lower limb equivalent of the triceps), which has four heads, this would seem to make sense.

External links

• lesson4nervesofant&postarm at The Anatomy Lesson by Wesley Norman (Georgetown University)
• Anatomy at Dartmouth elbow/muscles/muscles2
• Anatomy at MUN msk/arm
• Dissection at tufts.edu
• http://anatomy.med.umich.edu/musculoskeletal_system/axilla_ans.html

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