Forearm – Flexor and Extensor Compartments

Learning Objectives

After reading this post you will know:

  • Names of the superficial muscles in the flexor compartment of  forearm.
  • Names of deep muscles in the flexor compartment of  forearm.
  • Origin , insertion, action and nerve supply of muscles of flexor compartment of forearm.
  • Names of the  muscles in the externsor compartment of  forearm.
  • Origin , insertion, action and nerve supply of muscles of flexor compartment of forearm.

Q.  Enumerate:

  1. Superficial muscles of flexor compartment of forearm
  2. Deep muscles of flexor compartment of arm
  3. Muscles of flexor compartment of arm innervated by median nerve
  4. Muscles of flexor compartment of arm innervated by ulnar nerve
  5. Structures passing superficial to the flexor retinaculum
  6. Structures passing  deep to flexor retinaculum (through the carpal tunnel)

A.1. Superficial muscles of flexor compartment of forearm

  • Pronator teres
  • Flexor carpi radialis
  • Palmaris longus
  • Flexor digitorum superficialis
  • Flexor carpi ulnaris

    2. Deep muscles of flexor compartment of forearm

  • Flexor pollicis longus
  • Flexor digitorum profundus
  • Pronator quadratus

    3. 6 ½  muscles of flexor compartment of forearm  are innervated by median  nerve

  • Pronator teres
  • flexor carpi radialis
  • Palmaris longus
  • Flexor digitorum superficialis
  • Flexor pollicis longus
  • Flexor digitorum profundus ( laterl ½ )
  • Pronator quadrates

   4. 1 ½ muscles innervated by ulnar nerve 

  • Flexor carpi ulnaris
  • Flexor digitorum profundus ( medial ½ )

   5. Structures passing superficial to the flexor retinaculum (From lateral to medial side) :

  • Palmar cutaneous branch of median nerve
  • Tendon of Palmaris longus
  • Palmar cutaneous branch of ulnar nerve
  • Ulnar artery
  • Ulnar nerve

   6. Structures passing  deep to flexor retinaculum (through the carpal tunnel) are :

  • Flexor digitorum superficialis tendons
  • Flexor digitorum profundus tendons

( Long flexor tendons share the same synovial sheath, referred to as the ulnar bursa)

  • Flexor pollicis longus tendon which has its own synovial sheath, named the radial bursa.
  • Median nerve.

Q. Write in a tabulated form the origin, insertion, action and nerve supply of superficial muscles of flexor compartment of forearm.

A.  Superficial Muscles of Flexor  Compartment of Forearm

muscles of superficial compartment of forearm

Q. Write in a tabulated form the origin, insertion, action and nerve supply of deep muscles of flexor compartment of forearm.

A.  Deep Muscles of Flexor Compartment of Forearm

deep flexor muscles of flexor compartment of forearm

Q. Enumerate the structures passing deep to the extensor retinaculum:

A. Structures passing deep to extensor retinaculum:

The space deep to extensor rinaculum is divided into six compartments by fibrous septa extending from the deep surface of extensor retinaculum to the dorsal aspect of the lower ends of  radius and ulna. The structures passing through these 6 compartments from lateral to medial are:

  1. Abductor pollicis longus and extensor pollicis brevis
  2. Extensor pollicis longus
  3. Extensor carpi radialis longus and brevis
  4. Extensor digitorum , extensor indicis, posterior interrosseous nerve and anterior interrosseous artery.
  5. Extensor digiti minimi
  6. Extensor carpi ulnaris

Q. Write in a tabulated form the origin, insertion, action and nerve supply of superficial muscles of extensor compartment of forearm.

A. Superficial Muscles of Extensor Compartment of Forearm

superficial extensor muscles of forearm

Q. Write in a tabulated form the origin, insertion, action and nerve supply of deep muscles of extensor compartment of forearm.

A. Deep Muscles of Extensor Compartment of Forearm

deep muscles of extensor compartment

 

 

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