Which styloid process points to the thumb

Constitutional Law. Contract Law. Corporate Law. Criminal Law. Florida Bar Exam. Insurance Law. Intellectual Property. International Law. Legal Studies. Pharmacy Law. Property Law. Real Estate Law. Texas Bar Exam. Alternative Medicine.

Health Class. Health Science. Human Development. Mental Health. Public Health. ACE Health Coach. Real Estate. Computer Programming. Computer Science. Graphic Design. Information Security. Information Technology. Management Information Systems. Culinary Arts. Art History. Other Fine Arts. Cultural Literacy. Knowledge Rehab. National Capitals. People You Should Know. Sports Trivia. Learning Objectives Discuss the radius and ulna. Key Points The radius and the ulna are long, slightly curved bones that lie parallel from the elbow, where they articulate with the humerus, to the wrist, where they articulate with the carpals.

The radius is located laterally, near the thumb, and the ulna medially, near the little finger. The radius and the ulna have a styloid process at the distal end; they are also attachment sites for many muscles. The radius is smaller than the ulna. Key Terms radius : One of two forearm bones, it is located laterally to the ulna.

The Ulna Anatomically, the ulna is located medially to the radius, placing it near the little finger. Proximally, there are five key regions of the ulna: The olecranon is a projection of bone that extends proximally from the ulna. The triceps brachii muscle attaches to the ulna superiorly. The expanded distal end of each metacarpal bone articulates at the metacarpophalangeal joint with the proximal phalanx bone of the thumb or one of the fingers.

The distal end also forms the knuckles of the hand, at the base of the fingers. The metacarpal bones are numbered 1—5, beginning at the thumb. The thumb pollex is digit number 1 and has two phalanges, a proximal phalanx, and a distal phalanx bone see Figure 6.

Digits 2 index finger through 5 little finger have three phalanges each, called the proximal, middle, and distal phalanx bones. An interphalangeal joint is one of the articulations between adjacent phalanges of the digits. Visit this site to explore the bones and joints of the hand. What are the three arches of the hand, and what is the importance of these during the gripping of an object?

Due to our constant use of the hands and the rest of our upper limbs, an injury to any of these areas will cause a significant loss of functional ability. Many fractures result from a hard fall onto an outstretched hand. The resulting transmission of force up the limb may result in a fracture of the humerus, radius, or scaphoid bones.

These injuries are especially common in elderly people whose bones are weakened due to osteoporosis. Falls onto the hand or elbow, or direct blows to the arm, can result in fractures of the humerus Figure 6. Following a fall, fractures at the surgical neck, the region at which the expanded proximal end of the humerus joins with the shaft, can result in an impacted fracture, in which the distal portion of the humerus is driven into the proximal portion.

Falls or blows to the arm can also produce transverse or spiral fractures of the humeral shaft. In children, a fall onto the tip of the elbow frequently results in a distal humerus fracture. In these, the olecranon of the ulna is driven upward, resulting in a fracture across the distal humerus, above both epicondyles supracondylar fracture , or a fracture between the epicondyles, thus separating one or both of the epicondyles from the body of the humerus intercondylar fracture.

With these injuries, the immediate concern is possible compression of the artery to the forearm due to swelling of the surrounding tissues. If compression occurs, the resulting ischemia lack of oxygen due to reduced blood flow can quickly produce irreparable damage to the forearm muscles.

In addition, four major nerves for shoulder and upper limb muscles are closely associated with different regions of the humerus, and thus, humeral fractures may also damage these nerves. This involves a complete transverse fracture across the distal radius that drives the separated distal fragment of the radius posteriorly and superiorly.

This is the most frequent forearm fracture and is a common injury in persons over the age of 50, particularly in older women with osteoporosis. It also commonly occurs following a high-speed fall onto the hand during activities such as snowboarding or skating. The most commonly fractured carpal bone is the scaphoid, often resulting from a fall onto the hand. Deep pain at the lateral wrist may yield an initial diagnosis of a wrist sprain, but a radiograph taken several weeks after the injury, after tissue swelling has subsided, will reveal the fracture.

Due to the poor blood supply to the scaphoid bone, healing will be slow and there is the danger of bone necrosis and subsequent degenerative joint disease of the wrist. Watch this video to learn about a Colles fracture, a break of the distal radius, usually caused by falling onto an outstretched hand. When would surgery be required and how would the fracture be repaired in this case?

Skip to main content. Chapter 6: The Skeletal System. Search for:. Bones of the Upper Limb Learning Objectives Identify the divisions of the upper limb and describe the bones in each region List the bones and bony landmarks that articulate at each joint of the upper limb.

Interactive Link Watch this video to see how fractures of the distal radius bone can affect the wrist joint. Interactive Link Visit this site to explore the bones and joints of the hand.

Disorders of the Appendicular System: Fractures of the Upper Limb Bones Due to our constant use of the hands and the rest of our upper limbs, an injury to any of these areas will cause a significant loss of functional ability.