The trochlear spine is a bony protrusion at the back of the scapula bone. Its spelling can be a bit confusing, as it includes the "ch" digraph that can be pronounced differently in different words. In this case, "ch" is pronounced as a voiceless velar fricative (represented in IPA as /x/), similar to the "kh" sound in some dialects of English. The rest of the word is spelled phonetically, with "trochlear" pronounced as /tɹʌkliɚ/ and "spine" pronounced as /spaɪn/.
Trochlear spine refers to a prominent bony projection found on the posterior aspect of the scapula bone. Also known as the supraglenoid tubercle or the infraglenoid tubercle, it is located near the glenoid cavity and forms a key attachment site for various muscles and ligaments in the shoulder region.
The trochlear spine is characterized by its protruding shape, resembling a small prominence or tubercle. It is divided into two segments, the supraglenoid and infraglenoid tubercles, based on their relative positions above or below the glenoid cavity.
This bony structure plays a vital role in the movement and stability of the shoulder joint. It serves as an attachment site for the long head of the biceps brachii muscle and the superior glenohumeral ligament. These connections ensure optimal function, control, and stability of the shoulder during various movements.
Moreover, the supraglenoid tubercle, especially, acts as the origin point for the long head of the biceps brachii muscle, an important flexor and supinator of the forearm. Along with its neighboring structures, the trochlear spine contributes to the coordinated motion and overall stability of the shoulder complex.
In summary, the trochlear spine is a prominent bony projection on the scapula bone, specifically located near the glenoid cavity. It facilitates the attachment of crucial muscles and ligaments, supporting shoulder joint movement and stability.
Spina trochlearis.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
The word "trochlear spine" has a relatively straightforward etymology.
The term "trochlear" comes from the Latin word "trochlea", meaning "a pulley". It originally referred to a mechanism consisting of a grooved wheel with a rope or chain running through it, used to lift heavy objects. In anatomy, the trochlea refers to a rounded structure or surface that acts as a pulley, guiding the movement of a tendon or muscle.
The word "spine" has its roots in Latin as well, derived from the Latin word "spina" meaning "thorn" or "spine". In anatomy, "spine" refers to a slender, pointed, or thorn-like structure, often serving as a projection or process on a bone.