Diplomate, American Board of Orthopedics

Spinal Surgery, Joint Surgery,  

Hand Surgery, Pain Management

Please see locations page for phone numbers of each clinic

 

E-mail us at:   contact@ahmedmedical.com

Home Sitemap Contact
Sub Links
 
Spine
Shoulder
Elbow
Knee
Hand and foot disorders
Orthopedics
Arthritis
Total joint replacement
Congenital disorders
Arthroscopy
 
     
 
Hand and foot disorders
 

Hand

In the human body, the carpal tunnel or carpal canal is the fibro-osseous passageway on the palmar side of the wrist that connects the distal forearm to the middle compartment of the deep plane of the palm. The canal is narrow and when any of the ten long flexor tendons passing through it swells or degenerates, the narrowing of the canal often results in the median nerve getting entrapped or compressed, a medical condition known as carpal tunnel syndrome.

A total of nine flexor tendons (not the muscles themselves) pass through the carpal tunnel:

A single nerve passes through the tunnel: the median nerve between tendons of flexor digitorum profundus and flexor digitorum superficialis

Structure

The carpus, the bony elements of the wrist, form an arch which is convex on the dorsal side of the hand and concave on the palmar side. The groove on the palmar side, the sulcus carpi, is covered by the flexor retinaculum, a sheath of tough connective tissue thus forming the carpal tunnel.

The narrowest section of the tunnel is located a centimetre beyond the mid-line of the distal row of carpal bones where the sectional area is limited to 1.6 cm2.

The tendons of the flexor digitorum superficialis and profundus pass through a common ulnar sheath, while the tendon of the flexor pollicis longus passes through a separate radial sheath. The mesotendon shared by these tendons is attached to the radial and palmar walls of the carpal tunnel.

Superficial to the carpal tunnel and the flexor retinaculum, the ulnar artery and ulnar nerve pass through the ulnar tunnel.

Effect of wrist movements

Movements in the wrist affects the shape and width of the carpal tunnel. The width decreases considerably during normal range of motion in the wrist and because the carpal bones move in relation to each other with every motion of the hand the bony walls of the tunnel are not rigid. Both flexion and extension increase compression in the carpal tunnel:

  • Flexing the wrist causes the flexor retinaculum to move closer to the radius which considerably decreases the cross section of the proximal opening of the tunnel. Additionally, the distal end of the capitate presses into the opening.
  • In extreme extension. the lunate constricts the passage as it is pressed toward the interior of the tunnel.

Foot

The foot is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is a separate organ at the terminal part of the leg made up of one or more segments or bones, generally including claws or nails.

Anatomy

The human foot and ankle is a strong and complex mechanical structure containing 26 bones, 33 joints (20 of which are actively articulated), and more than a hundred muscles, tendons, and ligaments.

An anthropometric study of 1197 North American adult Caucasian males (men age 35.5 years) found that a man"s foot length was 26.3 cm with a standard deviation of 1.2 cm.

The foot can be subdivided into the hindfoot, the midfoot, and the forefoot:

The hindfoot is composed of the talus or ankle bone and the calcaneus or heel bone. The two long bones of the lower leg, the tibia and fibula, are connected to the top of the talus to form the ankle. Connected to the talus at the subtalar joint, the calcaneus, the largest bone of the foot, is cushioned inferiorly by a layer of fat.

The five irregular bones of the midfoot, the cuboid, navicular, and three cuneiform bones, form the arches of the foot which serves as a shock absorber. The midfoot is connected to the hind- and fore-foot by muscles and the plantar fascia.

The forefoot is composed of five toes and the corresponding five proximal long bones forming the metatarsus. Similar to the fingers of the hand, the bones of the toes are called phalanges and the big toe has two phalanges while the other four toes have three phalanges. The joints between the phalanges are called interphalangeal and those between the metatarsus and phalanges are called metatarsophalangeal (MTP).

 

The information contained above is for educational purposes only.  If you have
any questions relating to this or to any other orthopedic conditions, please consult
a board-certified orthopedic surgeon.

 
     
Copyright © 2009. Ahmed Medical. All Rights Reserved.