distal

Examples of distal in the following topics:

• Carpals, Metacarpals, and Phalanges (The Hand)

  • In the distal row contains the trapezium, trapezoid, capitate and hamate moving lateral to medial.
  • The trapezium articulates with the scaphoid proximally and the first, thumb, and second metacarpal distally.
  • The trapezoid articulates with the scaphoid proximally and the second metacarpal distally.
  • The length of the phalanges decreases distally.
  • Fingers are made up of proximal, intermediate and distal phalanges.

• Tarsals, Metatarsals, and Phalanges (The Foot)

  • The tarsal bones of the foot are organized into three rows; proximal, intermediate and distal.
  • It articulates with the talus superiorly and anteriorly with the cuboid of the distal group.
  • There are four distal tarsals, the lateral cuboid and the medial three cuneiforms.
  • The distal tarsals articulate with the metatarsals and also maintain the transverse arch of the foot.
  • The length of the phalanges decreases distally.

• Ulna and Radius (The Forearm)

  • Finally, immediately distal to the coronoid process is the tuberosity of ulna to which the brachialis muscle attaches.
  • Distally the ulna is much small and terminates with a rounded head which articulates with the ulnar notch of the radius to form the distal radioulnar joint.
  • The styloid process of the ulna extends distally and is the site of attachment for ligaments found in the wrist.
  • The radius is slightly smaller than the ulna and pivots around the ulna to produce movement at the proximal and distal radioulnar joints.
  • Distally the radius expands, medially the ulnar notch articulates with the head of the ulnar.

• Femur (The Thigh)

  • The femur articulates proximally with the acetabulum of the pelvis forming the hip joint, and distally with the tibia and patella to form the knee joint.
  • Two key features of the shaft are the proximal gluteal tuberosity to which the gluteus maximus attaches and the distal adductor tubercle to which the adductor magnus attaches.
  • Distally the femur exhibits five key regions.

• Nephron, Parts, and Histology

  • It transfers fluid from the proximal to the distal tubule.
  • The distal convoluted tubule and collecting duct is the final site of reabsorption in the nephron.
  • The collecting duct is similar in function to the distal convoluted tubule and generally responds the same way to the same hormone stimuli.
  • The osmolarity of fluid through the distal tubule and collecting duct is highly variable depending on hormone stimulus.
  • Distal tube, 7.

• Tibia and Fibula (The Leg)

  • The tibia, or shin bone, spans the lower leg articulating proximally with the femur and patella at the knee joint and distally with the tarsal bones to form the ankle joint.
  • Distally the tibia also widens to aid with weight bearing and it displays two key features.
  • Distally the fibula forms the lateral malleolus, which is more prominent than the medial malleolus of the tibia and also articulates with the tarsal bones forming the ankle joint.

• Humerus (The Upper Arm)

  • Distally the humerus articulates with the radius and ulna to form the elbow joint.
  • Distally the humerus flattens to articulate with the ulna and radius at the elbow joint.
  • The humerus attaches proximally to the scapula (shoulderblade) at the humeral head and distally with the radius and ulna (lower-arm bones) at the trochlea and capitulum, respectively.

• Regeneration of Nerve Fibers

  • When an axon is damaged, the distal segment undergoes Wallerian degeneration, losing its myelin sheath.
  • Axonal sprouts form at the proximal stump and grow until they enter the distal stump.
  • When a nerve axon is severed, the end still attached to the cell body is labeled the proximal segment, while the other end is called the distal segment.
  • The distal segment, however, experiences Wallerian degeneration within hours of the injury; the axons and myelin degenerate, but the endoneurium remains.
  • Slower degeneration of the distal segment than that which occurs in the peripheral nervous system also contributes to the inhibitory environment; inhibitory myelin and axonal debris are not cleared away as quickly.

• Muscles of the Humerus that Act on the Forearm

  • Forearm rotation is controlled by two joints, the proximal radioulnar joint which exists immediately below the elbow, and the distal radioulnar joint located immediately before the wrist.
  • Brachialis - The brachialis muscle lies within the distal region of the biceps brachii.
  • Attachments - The long head originates from the scapula, the lateral head from the proximal region of the humerus and the medial head from the distal region of the humerus.
  • Attachments - The pronator teres has two origins, one on the proximal end of the humerus and one of the distal end of the ulna, it attaches to the mid region of the radius.
  • Attachments - Originates from the humerus and attaches to the distal end of the radius.

• Directional Terms

  • Proximal and Distal: are terms that describe one point relative to another.
  • Proximal refers to a point closer to the reference point while distal refers to a point farther away.
  • When describing appendages the proximal end of the appendage connects the appendage to the rest of the body, while the distal end is the end of that appendage that is away from the body.