Introduction

The objective of this comprehensive, academic, in-depth, and well-hierarchized course is to provide a thorough understanding of "The Carpus". This course falls under the category of "Osteology".

Importance of the Carpus

The carpus, also known as the wrist, is a complex region in the human skeleton that plays a crucial role in our daily activities. Understanding its anatomy, function, and clinical relevance is essential for anyone studying biology or medicine.

The Carpal Bones

This section will delve into the eight bones that constitute the carpus:

Scaphoid

Origin and Articulations

The scaphoid bone is one of the most frequently fractured carpal bones. It originates from the proximal row of carpal bones, situated between the lunate and the triangular bones. The scaphoid articulates with four other carpal bones: the lunate, the triangle bone, the trapezium, and the trapezoid.

Shape and Function

The scaphoid is shaped like an inverted "S" or a boat paddle. Its concave side faces distally while its convex side faces proximally. The scaphoid serves as a pivot point for wrist movements such as flexion, extension, ulnar deviation, and radial deviation.

Lunate

Origin and Articulations

The lunate bone is another proximal carpal bone that articulates with the scaphoid, triangular bone, hamate, capitate, and the distal radius. It is shaped like a quarter moon, hence its name. The concave surface of the lunate faces proximally, while its convex surface faces distally.

Shape and Function

The lunate plays a vital role in transmitting forces between the forearm bones and the hand. Its unique shape allows it to maintain stability during various wrist movements.

Triangular Bone (Triquetrum)

Origin and Articulations

The triangular bone is a carpal bone located in the proximal row, as its name suggests, it has a triangular shape. It articulates with the lunate, scaphoid, and the pisiform bone. The articular surface facing the distal radius forms part of the radiocarpal joint.

Shape and Function

The triangular bone acts as a stabilizer during radial deviation and provides support to the wrist. Its unique shape allows it to resist forces applied in various directions, ensuring wrist stability.

Pisiform Bone

Origin and Articulations

The pisiform bone is a small carpal bone located in the carpal tunnel. It articulates with the triangular bone, the hamate, and the navicular bone. The articular surface facing the flexor carpi ulnaris forms part of the radiocarpal joint.

Shape and Function

The pisiform bone serves as a fulcrum for the flexor carpi ulnaris muscle during gripping actions. It also provides stability to the wrist during movements such as radial deviation.

Hamate Bone

Origin and Articulations

The hamate is one of the two bones in the distal row of carpal bones. It articulates with the lunate, triangular bone, pisiform bone, capitate, and the fourth metacarpal bone. The articular surface facing the trapezoid forms part of the midcarpal joint.

Shape and Function

The hamate's hook-like process serves as an attachment site for several muscles, tendons, and ligaments. It also acts as a stabilizer during wrist movements such as flexion, extension, ulnar deviation, and radial deviation.

Capitate Bone

Origin and Articulations

The capitate is the largest bone in the distal row of carpal bones. It articulates with the hamate, lunate, scaphoid, and the second and third metacarpal bones. The articular surface facing the trapezium forms part of the scaphotrapezial joint.

Shape and Function

The capitate acts as a fulcrum for muscles during gripping actions. Its spherical shape allows it to transmit forces efficiently between the carpal bones and the metacarpal bones.

Trapezoid Bone

Origin and Articulations

The trapezoid is another bone in the distal row of carpal bones. It articulates with the scaphoid, capitate, hamate, and the second metacarpal bone. The articular surface facing the trapezium forms part of the scaphotrapezial joint.

Shape and Function

The trapezoid acts as a stabilizer during wrist movements such as flexion, extension, ulnar deviation, and radial deviation. Its unique shape allows it to resist forces applied in various directions, ensuring wrist stability.

Trapezium Bone

Origin and Articulations

The trapezium is the largest bone in the distal row of carpal bones. It articulates with the scaphoid, lunate, capitate, hamate, first metacarpal bone, and the radius. The articular surface facing the second metacarpal bone forms part of the carpometacarpal joint.

Shape and Function

The trapezium serves as a base for several muscles that control wrist and finger movements. Its unique shape allows it to transmit forces efficiently between the carpal bones, the radius, and the metacarpal bones.

Clinical Relevance of Carpal Bones

This section will discuss the common injuries and disorders associated with the carpal bones, their causes, symptoms, diagnosis, treatment, and prevention.