Vertebrae Individual vertebrae are found in the cervical, thoracic and lumbar regions of the vertebral column. There are significant differences between the vertebrae in each of these regions that you should know.
Cervical vertebrae – C1- C7 Body is oval; spinous process is short (except C-7) and sometimes split; Large vertebral foramen Transverse foramen for vertebral artery to brainstem. C1 is Atlas articulates (atlanto-occipital joint) with occipital bone of skull -allows “yes” motion of head C2 is Axis characterized by peg-like process called “dens” or odontoid process which interlocks with atlas (atlanto-axial joint) -allows sideward rotation or “no” motion of head.
Thoracic vertebrae T1- T12 Body is roughly heart shaped Demifacets for rib articulation Vertebral foramen are circular Spinous process long and points inferiorly The thoracic vertebra look like a giraffe’s head when viewed from the lateral view!
Lumbar Vertebrae L1-L5 Pedicles and laminae are short and thicker Spinous processes are short, flat and hatchet shaped Vertebral foramen is triangular Inferior and superior processes lock the adlacent vertebrae together for strength and stability. The lumbar vertebra look like a Moose’s head!
Sacral Vertebrae S1-S5 Sacral vertebrae consists of 5 fused vertebrae fully fused by 30 years of age Women sacrum is shorter, wider and more curved Connects the spine to the pelvic girdle at the sacroiliac joint. Sacral canal is continuation of vertebral canal.
Coccyx Vertebrae Co1-Co4 Coccyx is Greek for “cuckoo” Consists of 4 fused vertebrae Fuse between 20 and 30 years Tailbone is vestige of tail - Men it points anteriorly - Women it points inferiorly
Additional structures of the vertebral column Intervertebral discs Present between all vertebrae C2- L5/S1; Composed of fibro cartilage Two regions of disc: - nucleus pulposis – central core of disc - annulus fibrosis - outer covering of fibro cartilage Function: -discs permit various movements -provide shock absorbing functions for vertebral column
Vertebral Ligaments(1). Anterior and posterior longitudinal ligaments hold vertebral column together along with trunk skeletal muscles -prevent hyper-extension and hyper-flexion of the vertebral column.(2). Shorter ligaments connect adjoining vertebrae together. -There are 3 of these ligaments the ligamentum flavum, the supraspinous ligaments and the interspinous ligaments.
Bony Thorax Consists of ribs attached to the vertebral column and sternum True ribs R1-R7 attach directly to sternum False ribs R8-R10 attach indirectly Two floating ribs R11 & R12 The Sternum consisting of: - manubrium - body - Xiphoid process
Ribs1. true ribs – the first (superiormost) seven pairs of ribs R1-R7 are directly connected to the sternum via costal cartilage. - are called vertebrosternal ribs.2. false ribs – the remaining five pairs of ribs. There are two types of false ribs. vertebrochondral ribs -- rib pairs #8, #9, and #10 are connected by a single band of costal cartilage to the inferior portion of the sternum. Unlike the first seven pairs of ribs they do not have their own individual attachments. floating or vertebral ribs – rib pairs #11 and #12 are connected only to the vertebral column, they have no anterior connection to the skeleton.
All ribs articulate with vertebral column. The head of the rib articulates at a demifacet on the body of the vertebrae, while the tubercle of the rib articulates at a facet on the transverse process.
Sternum “breast plate” Anterior central portion of thorax Only bony attachment of axial skeleton to appendicular skeleton via clavicle. Consists of Manubrium, Body and Xiphoid process Key landmarks: calvicular notches, jugular notch “suprasternal notch”, sternal angle.
SternumThe sternal foramen is an anomaly and occurs in ~ 4-10% of the population. It can be mistaken for a bullet puncture in cases of traumatic death.
Hyoid bone Lies inferior to the mandible Is not attached to skeleton by bony means Helps movement of base of tongue