A sharp-pointed, hardened structure derived from a leaf, stipule, root or branch, but always originating from the vascular or woody part. (Thorn is derived from a reduced branch, pointed structures from the epidermis are called prickles).
A firm, slender, sharp-pointed structure, representing a modified leaf or stipule; more loosely, a structure having the appearance of a true spine.
A sharp-pointed, stiff, woody part of a plant; typically evolved from a leaf or stipule (compare to “prickle” and “thorn”).
A sharp more or less woody or horny outgrowth from a leaf or a part of a leaf, sometimes representing the entire leaf. The term has been applied sometimes to similar outgrowths from the stem.
A leaf or portion of a leaf that is sharp-pointed, the most common examples being paired stipular spines; not to be confused with thorns, which are modified stems or prickles, which are mere outgrowths of the epidermis, as in the cultivated rose.
The pendant, toothlike, spore-bearing structures characteristic of the tooth fungi.
A sharp, stiff outgrowth on a plant stem.
In anatomy, the backbone; the vertebrae.
The series of bones, the vertebrae, linked together to form a flexible supporting column running from the pelvis to the skull.
Any sharp projecting part of a bone.
In botanical usage a stiff, sharply pointed organ usually considered to be a modification of a leaf, stipule, bract or sepal.
Vertical column of bones composed of 24 individual vertebrae plus the sacrum and coccyx.
The column of bones and cartilage that extends down the back, supporting the head and torso and enclosing the spinal cord.
A collective term encompassing the series of bones known as vertebrae, the intervertebral disks, and the spinal cord, constituting the entirety of the backbone.
The series of bones and cushioning cartilage that stretches from the bottom of the skull to the pelvic region serves to encase the spinal cord and provide support for the torso and head.
The spinal column consists of 33 vertebrae, which are approximately cylindrical in shape. Adjacent pairs of these bones are linked by facet joints, serving both to secure the spine and facilitate its movement. Sandwiched between the vertebrae are cushions made of durable, fibrous cartilage with a gel-like center, known as intervertebral discs. These cushions function as shock absorbers during activities like running and jumping.
In a typical spinal structure, the uppermost segment, which comprises seven vertebrae and is referred to as the cervical spine, has a forward curve. The thoracic spine, consisting of 12 vertebrae located at the back of the chest, curves in the opposite direction, or backward. The lumbar section, or the lower back, also has a forward curve, especially noticeable in women. Finally, the section near the pelvis exhibits a backward curve.
The spinal column houses the spinal cord, which is a conduit of nerve pathways originating from the brain. Nerves stemming from the spinal cord, known as spinal nerves, emerge at the nerve roots. These then develop into peripheral nerves, whose roots navigate through gaps between the vertebrae to reach all areas of the body.
The vertebrae are interconnected by two extensive, robust ligaments that span the entire length of the spinal column, as well as by smaller ligaments linking the individual bones. Affixed to the spine are multiple muscle groups that regulate its motion and offer additional support.